Apply measures to Lookup

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ivancf1995
Junior Member
Posts: 4
Joined: Mon Oct 07, 2024 9:59 am
Vensim version: PLE

Apply measures to Lookup

Post by ivancf1995 »

Good morning,

I have some model predictions imported to Vensim as data as a Lookup structured like: [(1960,893.015)-(2070,32121.347)],(1961,32113.695),(1962,32105.358),(1963,32096.276)...The model is complex, so I cannot do it directly in VENSIM.

My question is: how can I apply certain conditions to this data within Vensim? For example, let’s say that based on a binary switch, if the year is greater than 2040, I want the predicted population value to remain constant from 2040 to 2070, instead of growing.

Thank you in advance

Iván
Administrator
Super Administrator
Posts: 4681
Joined: Wed Mar 05, 2003 3:10 am

Re: Apply measures to Lookup

Post by Administrator »

This is just a guess as you haven't provided much to go on.

CONSTANT POPULATION GROWTH RATE = 30?
CONSTANT POPULATION GROWTH RATE START TIME = 2040 {year}
CONSTANT POPULATION GROWTH RATE END TIME = 2070 {year}

IF THEN ELSE ( time > CONSTANT POPULATION GROWTH RATE START TIME
:and: time < CONSTANT POPULATION GROWTH RATE END TIME
, CONSTANT VALUE
, lookup table (time) )
Advice to posters seeking help (it really helps us to help you)
http://www.ventanasystems.co.uk/forum/v ... f=2&t=4391

Units are important!
http://www.bbc.co.uk/news/magazine-27509559
ivancf1995
Junior Member
Posts: 4
Joined: Mon Oct 07, 2024 9:59 am
Vensim version: PLE

Re: Apply measures to Lookup

Post by ivancf1995 »

Hi Admin,

thank you for your quick response. It was finally solved using your suggestion and changing de Data Table from "Lookup" to "Auxiliary with Lookup". Now I have another doubt. ¿Can I extract a value from the Data Table of a certain Year and save it as a constant? For example, Data Table contains values from 2000 to 2070, and I want to store the 2025 value to use it in other parts of the model. Such as:
"IF THEN ELSE(Time<ShortTerm,Lookup table,2025_value)"

Thank you in advance
Administrator
Super Administrator
Posts: 4681
Joined: Wed Mar 05, 2003 3:10 am

Re: Apply measures to Lookup

Post by Administrator »

You can use something like
value at 2025 = initial ( Lookup table(2025) )
Advice to posters seeking help (it really helps us to help you)
http://www.ventanasystems.co.uk/forum/v ... f=2&t=4391

Units are important!
http://www.bbc.co.uk/news/magazine-27509559
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